1. Field of the Invention
The present invention relates to a squeeze roller of a liquid toner type image formation apparatus.
2. Description of the Related Art
Conventionally, in a roller made from a metal pipe rotating while applying a load, pressure is made uniform with respect to the roller longitudinal direction utilizing the elasticity of the metal pipe as follows. The metal pipe and a shaft portion are fixed to each other with a metal pin or the metal pipe and the shaft portion are connected to each other by press fit. However, there is a problem that in the aforementioned roller, the pressure of the connected portion becomes high and it is impossible to obtain a uniform pressure in the roller longitudinal direction.
Moreover, as means for eliminating a high pressure portion, there is means to apply an adhesive in the clearance between the metal pipe and the shaft portion. However, in the aforementioned roller, after rotated with a load for a long period of time, the fixing force at a portion attaching the shaft portion to the metal pipe becomes weaker and a sliding occurs between the shaft portion and the metal piping, disabling to obtain a roller rotation matched with the rotation of the shaft portion.
The first problem of this conventional roller is that the pressure cannot be made uniform in the roller longitudinal direction. The reason is that the pressure of the connected portion becomes high.
The second problem is that it is impossible to obtain a roller rotation matched with the rotation of the shaft portion. The reason is that after a long period of use in rotation with a load, the fixing force at the portion where the shaft portion is attached to the metal pipe becomes weaker and sliding occurs between the shaft portion and the metal pipe.
It is therefore an object of the present invention to provide a liquid toner type image formation apparatus squeeze roller capable of generating a uniform pressure in the longitudinal direction of the roller portion and the roller portion can be rotated following the rotation of the shaft portion for a long period of time.
The liquid toner type image formation apparatus squeeze roller according to the present invention comprises: a roller portion having a metal pipe and an elastic body formed with a uniform thickness on the metal pipe; a press fit member inserted in the center portion of the metal pipe in the longitudinal direction; a shaft portion having a diameter reduced at both ends in the longitudinal direction and a center portion having a length almost identical to that of the press fit member and pressed against the inner surface of the press fit member; metal pins fixed at an identical distance from the center of the roller portion and the press fit member in the. longitudinal direction.
Moreover, in the liquid toner type image formation apparatus according to the present invention, the metal pins have a configuration connected only to the metal pipe and not connected to the shaft portion.
Furthermore, in the liquid toner type image formation apparatus squeeze roller according to the present invention, the press fit member is made from a resin or rubber having an elastic modulus smaller than that of the metal pipe.
Furthermore, in the liquid toner type image formation apparatus squeeze roller according to the present invention, the reduced diameter of the both ends of the shaft portion is such that the metal pipe deflected by a load during printing will not touch the shaft portion.
Furthermore, in the liquid toner type image formation apparatus squeeze roller according to the present invention, the metal pipe has such a thickness that an amount of deflection generated by a load during printing is identical to the amount of deflection of the backup roller.
Furthermore, the liquid toner type image formation apparatus squeeze roller according to the present invention is rotated according to the progress direction of a photosensitive belt having a photosensitive body while applying a load of 20 kgf or above to the backup roller via the photosensitive belt, so that a solvent of a liquid toner is removed from an image developed on the photosensitive belt.
Furthermore, the liquid toner type image formation apparatus squeeze roller according to the present invention is rotated, upon completion of a printing, in the opposite direction to the progress direction of the photosensitive belt while applying load of about 3 kgf to the backup roller via the photosensitive belt, so that the liquid toner remaining on the photosensitive belt is removed.